Permanent amplifying effect on the cockerel gonad of hypophysis hormones (FSH, TSH) administered at hatching.

The effect of TSH and FSH was studied by quantitative histological analysis of the gonads in five-week-old cockerels pre-treated with these hormones at hatching. It was concluded that (1) hypophyseal hormones of similar molecular structure are not fully specific in immature animals. At five weeks both FSH and TSH enhance spermatogonium division and spermatogenesis, and increase the number of Sertoli cells. (2) While a single post-hatching dose of hormone has no effect on germinal cells as studied in the fifth week it increases the number of Sertoli cells (3) post hatching FSH-treatment facilitates the effect of hormone treatment at five weeks, amplifying the effect of FSH slightly more than that of TSH. Post hatching TSH-treatment also amplifies the effect of FSH administered at five weeks but does not influence the effect of five-week TSH-treatment on germinal cells. (4) The present results have corroborated earlier findings based on the measurement of gonadal weight and tubule diameter.